Hi Sir /Mam.  It is common to have decreased appetite during fever. Once he recovers from fever he will start eating normally.  Sometimes it may take few more days even after fever subsides for the hunger to return. You must keep giving him lots of fluids to keep his body hydrated. Pls read these articles on fever. "My Child Has Fever! What to Do?" by Dr. Sreedhar RS ~ https://www.practo.com/healthfeed/my-child-has-fever-what-to-do-25940/post "Danger Signs in Fever" by Dr. Sreedhar RS ~ http://prac.to/59sh